Documentation/ABI/testing/sysfs-class-devfreq

   1 What:           /sys/class/devfreq/.../
   2 Date:           September 2011
   3 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
   4 Description:
   5                 Provide a place in sysfs for the devfreq objects.
   6                 This allows accessing various devfreq specific variables.
   7                 The name of devfreq object denoted as ... is same as the
   8                 name of device using devfreq.
   9
  10 What:           /sys/class/devfreq/.../governor
  11 Date:           September 2011
  12 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  13 Description:
  14                 The /sys/class/devfreq/.../governor show or set the name of the
  15                 governor used by the corresponding devfreq object.
  16
  17 What:           /sys/class/devfreq/.../cur_freq
  18 Date:           September 2011
  19 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  20 Description:
  21                 The /sys/class/devfreq/.../cur_freq shows the current
  22                 frequency of the corresponding devfreq object. Same as
  23                 target_freq when get_cur_freq() is not implemented by
  24                 devfreq driver.
  25
  26 What:           /sys/class/devfreq/.../target_freq
  27 Date:           September 2012
  28 Contact:        Rajagopal Venkat <rajagopal.venkat@linaro.org>
  29 Description:
  30                 The /sys/class/devfreq/.../target_freq shows the next governor
  31                 predicted target frequency of the corresponding devfreq object.
  32
  33 What:           /sys/class/devfreq/.../polling_interval
  34 Date:           September 2011
  35 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  36 Description:
  37                 The /sys/class/devfreq/.../polling_interval shows and sets
  38                 the requested polling interval of the corresponding devfreq
  39                 object. The values are represented in ms. If the value is
  40                 less than 1 jiffy, it is considered to be 0, which means
  41                 no polling. This value is meaningless if the governor is
  42                 not polling; thus. If the governor is not using
  43                 devfreq-provided central polling
  44                 (/sys/class/devfreq/.../central_polling is 0), this value
  45                 may be useless.
  46
  47 What:           /sys/class/devfreq/.../trans_stat
  48 Date:           October 2012
  49 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  50 Description:
  51                 This ABI shows the statistics of devfreq behavior on a
  52                 specific device. It shows the time spent in each state and
  53                 the number of transitions between states.
  54                 In order to activate this ABI, the devfreq target device
  55                 driver should provide the list of available frequencies
  56                 with its profile.
  57
  58 What:           /sys/class/devfreq/.../userspace/set_freq
  59 Date:           September 2011
  60 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  61 Description:
  62                 The /sys/class/devfreq/.../userspace/set_freq shows and
  63                 sets the requested frequency for the devfreq object if
  64                 userspace governor is in effect.
  65
  66 What:           /sys/class/devfreq/.../available_frequencies
  67 Date:           October 2012
  68 Contact:        Nishanth Menon <nm@ti.com>
  69 Description:
  70                 The /sys/class/devfreq/.../available_frequencies shows
  71                 the available frequencies of the corresponding devfreq object.
  72                 This is a snapshot of available frequencies and not limited
  73                 by the min/max frequency restrictions.
  74
  75 What:           /sys/class/devfreq/.../available_governors
  76 Date:           October 2012
  77 Contact:        Nishanth Menon <nm@ti.com>
  78 Description:
  79                 The /sys/class/devfreq/.../available_governors shows
  80                 currently available governors in the system.
  81
  82 What:           /sys/class/devfreq/.../min_freq
  83 Date:           January 2013
  84 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  85 Description:
  86                 The /sys/class/devfreq/.../min_freq shows and stores
  87                 the minimum frequency requested by users. It is 0 if
  88                 the user does not care. min_freq overrides the
  89                 frequency requested by governors.
  90
  91 What:           /sys/class/devfreq/.../max_freq
  92 Date:           January 2013
  93 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  94 Description:
  95                 The /sys/class/devfreq/.../max_freq shows and stores
  96                 the maximum frequency requested by users. It is 0 if
  97                 the user does not care. max_freq overrides the
  98                 frequency requested by governors and min_freq.
  99                 The max_freq overrides min_freq because max_freq may be
 100                 used to throttle devices to avoid overheating.